The present invention relates to catheter designs. In particular, it relates to a radiopaque indicator which may also be used as a plug in the lumen of a multi-lumen catheter.
Catheters are used in medical applications to introduce or extract fluids from the body. A variety of catheter designs have been used and are well known. Typically, catheters are flexible, plastic tubular structures having single or multiple openings called lumens. Many multiple lumen ("multi-lumen") catheters require plugging devices to terminate lumens at some opening along the catheter length.
The standard technology used for plugging lumens involves bonding a flexible plastic plug (using an adhesive or a solvent) into the lumen requiring the plug. The plastics used are normally soft, flexible, biomedically safe, radiopaque, and compatible with parent catheter materials. The limitation associated with using a plastic plugging material is principally one of radiopacity.
Radiopacity is important because it allows the physician to follow the catheter tip using a fluoroscope when the catheter is inserted into a patient. Accordingly, injury to the patient can be avoided. The degree of radiopacity of a plastic plug is determined by the amount of plastic filler, such as barium or bismuth, which the plastic contains. Typically, the filler concentration ranges from about 9% to about 24%. Although higher concentrations of radiopaque fillers are desirable, using existing technology, the filler percentage cannot be increased without losing the parent material's desirable properties, such as flexibility and strength.
Heretofore, metal radiopaque indicators, comprising solid metal bands formed around the exterior of a catheter, have been used. However, such exterior bands have the disadvantage of interrupting the smooth outer surface of the catheter as they may encourage thrombosis.